Vacuum cooling and drying apparatus for granular materials.



E. PASSBURG.

VACUUM COOLING AND DRYING APPARATUS FOR GBANULAR MATERIALS. APPLIOATION I'ILEDVJULY 15, 1912.

1 ,O98,363, Patented May 26, 1914 Fly. 2

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VACUUM COOLINQ AND DRYING-APPARATUS FOR GRANULAR MATERIALS.

To all whom it may concern: I Be it known that I, E1111. PASSBURG, engineer, a citizen of the German. Empire, residing at Berlin, Germany, have invented certain new and useful Improvements in Vacuum Coolingand Drying Apparatus for Granular Materials, of which the following is a specification. Q

My invention relates to apparatus for cooling warmed or predried granular materials particularly grain, under the action of a vacuum for storage purposes.

It has heretofore been attempted to cool dried material under a vacuum, but the known process could not be extensively used for large quantities of material, particularly for grain, in spite of'the long felt want of the grain issuing'continuously from a drier in a warm state, of which vessels one is charged with the material coming from the drier, the second previously charged vessel is being highly evacuated, and the third is being emptied of the material previously cooled therein by the vacuum. In this manner both constant reception of the material coming from the drier or heater and also a sufliciently long action of the vacuum on the vessel acting for the time being as cooler, z. e. continuous operation, is guaranteed.

One embodiment of my invention is represented by way of example in the accompanying drawing, wherein:

Figure 1 is a side elevation and Fig. 2 a trip plan view showing my improved cooling p ant.

Referring to the drawing, the cooling plant comprises at least three cooling vessels or containers at, b, c, which are connected by way of valves 1; with a drying apparatus 25,

Fig. 1 having a conveyer worm 25,, working under a vacuum or at atmospheric ressure.

Each cooler a, b, c, is connected with a device f for collecting the dust from the grain,

Specification of Letters Patent. Application filed July 15, 1912. Serial No. 709,443.

Patented May as, rare.

and each of these dust collectors is controlled by two valves 9 and 9 The valves 9 are connected by piping to a small condenser is connected with a common, ordinary airpump 0 for producing slight vacua, while the valves 91 are connected to the. condenser is, connected with an air-pump p for produc ing a high vacuum. Further, each cooler a, b, 0, possesses a discharge valve m for the discharge of the cooled grain. The temperature of the coolers can be read at the thermometers a".

This cooling and drying plant operates as follows :The heated grain runs out of the drying or heating apparatus 25 having the conveyer worm t into the cooler a, and when this cooler is' charged, its valve 0; is closed and the valve '0 of the cooler b is opened, whereupon the grain now runs into the cooler 12. Valve 9 in cooler a is opened, whereupon the air-pump 0 produces a vacuum of 27.to 28" in said cooler a, While the particles of dust carried along with the air a are retained in the dust collector f, which is filled with water, and only the pure vapor from the heated grain passes into the con denser is where it is condensed to some extent according to the vacuum obtained. The valve 9 is thenclosed and the valve 9 is opened, and a high vacuum of 29 to 29%" is then obtained in the cooling apparatus by means of the pump 1). Due to this high vacuum, the water in the warm grain evaporates at a temperature of from 3020 6., and consequently the grain is cooled at this temperature as the rising vapor condenses in the large condenser 70,,

wherein the grain is further dried when the water is mptied. This cooling produces at the same time a drying action, contrary to the known air cooling apparatus, in which it often happens that the dried grain again becomes wet owing'to the moisture of the air.

When the grain in the cooler a is suficiently cooled in consequence of the vapor-' ization of the water, the valve 'v of the cooler way cars, steamers or the like. In this manner the three coolers are filled, evacuated and emptied in turn, the current of grain continuously running into them out of the drier being continuously cooled and dried.

The air-pump is preferably formed as a compound air-pump in such manner that a vacuum of about 0.10 atm. pressure is first produced in the coolers by the air-pump cylinder 0 for low vacua, as described, before the cooler in questionvis connected to the airpump cylinder 29 for high vacua, While the pump cylinder 0 for low vacua sucks away the air behind the valves of the cylinder p for producing a high vacuum up to 0.08 atmo. or 0.016 atmo. in the pump cylinder'p. The small condenser 70 is not needed, if the grain leaving the drier has a temperature of not more than 404:5 C.- But if the grain is warmer, vapors arise at a vacuum of about 27" mercury column, which cannot be permitted to enter the pump 0, until they have been condensed in the condenser 70 continuous effective working of the pump p to obtain high vacuum, the main quantity of air'must be taken out of the cooler by the pump 0, which is connected with the pump 32; the latter is then only used to balance the difference of the low vacuum of 27 and the high vacuum of 29".

It is obvious that the pump 7) can permanently be used for high vacuum in the cool ers filled with air, Without the acting of the air pump 0, as described, but this operation has disadvantages.

I claim: v 1. Cooling and drying apparatus for warm granular materialcomprising at least three large vessels, a main drier; and means for producing a vacuum in each vessel, each of which vessels in turn is successively filled with the material, is subjected to a high vacuum to cool and dry the material, and discharges the cooled and dried material, said vessels being arranged below and connected with said main drier.

For

roeaaea 2. Cooling and drying apparatus for warm granular material comprising at least three vessels, each being provided with an inlet valve and an outlet valve; a main drier; an air-pump; a pipe connecting each vessel with the-airpump; and valves for controlling the connection of each vessel with! said pipe, each of said vessels being used in turn to successively receive, cool and dry under a high vacuum, and to discharge the cooled and dried material, said vessels being arranged below and connected with said main drier.

3. Cooling and drying apparatus for warm granular material comprising at least three vessels, each being provided with an inlet valve and an outlet valve; a main drier; a compound air-pump having a low vacuum cylinder and a high vacuum cylinder; a low vacuum pipe connecting the former cylinder with each vessel; a high vacuum pipe connecting the latter cylinder with each vessel; and valves for controlling the connection of each vessel with the said low vacuum and high vacuum pipes, said vessels being arranged below and connected with said main drier.

4. Cooling and drying apparatus for Warm granular material consisting, in combination with a main drier; of at least three ves sels, each of saidvessels being provided With an inlet valve-and an outlet valve; and an air-pump connected with each of said vessels, one of said vessels being connected by way of its inlet valve with the main drier, during the time that the second in turn, which has previously been filled, is connected with the air-pump and is being highly evacuated, and the third is being emptied.

In testimony whereof I hereunto affix my signature in the presence of two Witnesses.

EMIL PASSBURG.

Witnesses;

HENRY HASPER, WOLDEMAR HAUPT. 

